Development of a new method for synthesis, controlling the particle size and morphology of ZIF and considering its effect on the Oxygen reduction reaction

For the first time, this study examined one aspect of the synthesis conditions of zeolitic imidazolate framework (ZIF) and its impact on its morphology and structural properties. Specifically, the study investigated the effect of the time of adding the precursor on ZIF's properties. The study used various analytical techniques, including field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDS), N2 adsorption-desorption isotherms, BET, BJH, and XRD to investigate ZIF's properties. The study found that increasing the addition-precursor time effectively increased the particle size, and the surface area and pore size were affected by changing the time of addition. The study also examined the synthesis condition of electrocatalysts for the oxygen reduction reaction (ORR) in acidic media obtained from Fe/Co-ZIF-8(T) pyrolysis at 1000 °C. The study found that the precursors-adding time affected the graphitic structure after pyrolysis. The onset potential of Fe/Co-NC(10 h) was about 0.86 VRHE, and the limiting current density was about 4.38 mA cm−2 in a 0.5 M H2SO4 solution. The measured kinetic parameters showed that the electron transfer number (n) and the Tafel slope of Fe/Co-NC(10 h) were 3.91 and 74 mV dec−1, respectively. The results showed that by changing the time in the precursors-adding method, the ZIF crystal structure could be engineered, and extensive studies based on this synthesis method could be designed for structural engineering.